Developing cartridge, air communication unit of developing cartridge and toner cartridge

ABSTRACT

A developing cartridge  12  includes a housing  43  which has a peripheral surface and two end faces formed on both sides of the peripheral surface, and a toner containing space  45  which is formed in the housing and which contains toner  47  therein. A communication hole  61  is formed on a periphery surface of the developing cartridge  12.  The communication hole  61  is sealed by a sticker  63  which has minute holes for allowing air to flow and preventing the toner  47  from passing through.

TECHNICAL FIELD

This invention relates to a developing cartridge used with a laserprinter for storing toner and developing a latent image formed on aphotoconductor drum in the toner and in particular to a structure foradjusting the pressure in a housing of a developing cartridge attachedto a rotary developing unit for use.

BACKGROUND ART

In a laser printer including a rotary developing unit, a plurality ofdeveloping cartridges storing different color toners are set in therotary developing unit. At the printing time, while the rotarydeveloping unit is rotated, the developing cartridge storing thenecessary color toner is brought adjacent to a photoconductor drum, andthe toner is supported on a latent image formed on the photoconductordrum and is transferred from the photoconductor drum via a transfer beltto a sheet for fixation.

Since the toner stored in the developing cartridge is consumedgradually, a negative pressure may be developed in the developingcartridge because of a decrease in the volume occupied by the toner. Incontrast, it is also possible that the pressure in the sealed developingcartridge may rise because of the effect of heat from a heating elementpositioned in the proximity of the developing cartridge. If thedifference between the pressure in the developing cartridge and theatmospheric pressure is thus produced, the toner supply state from thedeveloping cartridge may worsen or toner may be supplied more thannecessary from the developing cartridge, degrading the quality of theimage of printed matter.

Hitherto, an air hole is formed on an end face of the housing of adeveloping cartridge. The air hole is sealed by a seal member forpreventing toner from flowing out, but allowing air to flow to put formaking the pressure in the developing cartridge equal to the atmosphericpressure, as disclosed in Patent document 1.

[Patent Document 1]

JP-A-6-324568

However, pressure adjustment according to the structure wherein thehousing is formed on the end face with an air hole as in the related artis attributed only to natural air communication caused by the differencebetween the pressure in the housing and the atmospheric pressure.Therefore, it takes some time until complete pressure adjustment ismade. If the pressure in the developing cartridge rises accompanying arapid temperature rise, there is also a possibility that a detrimentaleffect of excessive outflow of toner, etc., may be caused to occurbefore the pressure in the developing cartridge lowers.

DISCLOSURE OF THE INVENTION

It is therefore an object of the invention to provide a developingcartridge, an air communication unit of the developing cartridge, and atoner cartridge, using the fact that a rotary developing unit rotates ona rotation shaft to make it possible to forcibly discharge air in adeveloping cartridge or forcibly suck the outside air for promptlyadjusting the pressure in the developing cartridge.

To achieve the above object, according to a first aspect of theinvention, there is provided a developing cartridge, comprising: ahousing, which has a peripheral surface and two end faces formed on bothsides of the peripheral surface, a toner containing space surrounded bythe peripheral surface and two end faces which contains toner therein,and the housing having a communication hole which communicates the tonercontaining space with an exterior; and a sticker, which is arranged soas to seal the communication hole. The sticker has minute holes forallowing air to flow and preventing the toner from passing through.

According to the invention, the rotary developing unit rotates, wherebythe toner in the housing drops in a stroke, so that the air below thetoner at the time is pushed out in a stroke through the communicationholes formed in the lower side of the peripheral surface of the housingand on the other hand, the outside air can be forcibly sucked into thespace occupied by the toner through the communication holes formed inthe upper side of the peripheral surface of the housing.

As the developing cartridge according to a second aspect of theinvention, in the first aspect of the invention, the peripheral surfaceof the housing has an upper face and a lower face. The communicationhole is formed in either or both of the upper face and the lower face.

Air is pulled in through the communication hole formed in the upper faceof the peripheral surface of the housing in the beginning and air ispushed out through the communication hole formed in the lower face.Then, when the rotary developing unit rotates 180 degrees, thecommunication holes formed in the upper and lower faces function inopposite manner. Thus, whenever the rotary developing unit rotates, airis discharged and sucked alternately through the same communication holewith a move of toner, so that rapid pressure adjustment in the housingis made.

As the developing cartridge according to a third aspect of theinvention, in the first or second aspect of the invention, thedeveloping cartridge further including a developing roller whichprovides the toner in the toner containing space to the conductor drum,the developing roller having a rotation shaft to be rotatably attachedto the housing; and an abutment regulation roller, which regulates adistance between the developing roller and the conductor drum, and theabutment regulation roller attached to both ends of the rotation shaftof the developing roller. The communication hole is formed in thevicinity of the abutment regulation roller.

According to the invention, the toner drops in a stroke due to thevibration produced when the abutment regulation roller collides with theperipheral surface of the photoconductor drum, so that the dischargingeffect of the air in the housing and the suction effect of the outsideair into the housing are enhanced.

As the developing cartridge according to a fourth aspect of theinvention, in the third aspect of the invention, the communication holeis formed so as to correspond a position of the abutment regulationroller.

According to the invention, the vibration produced when the abutmentregulation roller collides with the peripheral surface of thephotoconductor drum propagates directly to the housing, so that thedischarging effect of the air in the housing and the suction effect ofthe outside air into the housing are still more enhanced.

As the developing cartridge according to a fifth aspect of theinvention, in the third or fourth aspect of the invention, thecommunication hole is constituted by a plurality of communication holes.One of the communication holes is formed at a center portion of thehousing.

According to the invention, the discharging effect of air and thesuction effect of the outside air into the housing in the vicinity ofthe center portion of the housing are provided, so that the dischargingeffect of air and the suction effect of the outside air in the wholehousing are enhanced.

As the developing cartridge according to a sixth aspect of theinvention, in the first aspect of the invention, the communication holeis constituted by a plurality of small holes. According to theinvention, the discharging effect of air and the suction effect of theoutside air can be more averaged.

As the developing cartridge according to a seventh aspect of theinvention, in the first aspect of the invention, the developingcartridge further including a label, which is put on the sticker. Thelabel is formed with an air hole for allowing air to flow.

According to the invention, the presence of the communication hole canbe hidden by the label. On the other hand, the label is formed with theair hole and thus the discharging effect of air and the suction effectof the outside air remain unchanged.

As the developing cartridge according to an eighth aspect of theinvention, in the first aspect of the invention, the developingcartridge including a label which is put on the housing so as to have agap between the label and the sticker. A communication passage whichcommunicates the gap to an atmosphere is formed.

According to the invention, even if a label not formed with an air holefor allowing air to flow is used, the label does not block the minuteholes of the sticker and the discharging effect of air and the suctioneffect can be provided.

As the developing cartridge according to a ninth aspect of theinvention, in the eighth aspect of the invention, the communication holeis provided on a bottom of a depression formed on the peripheral surfaceof the housing.

According to the invention, the depression is formed on the surface ofthe housing and the communication hole is provided on the bottom of thedepression, so that a gap can be easily provided between the sticker andthe label. That is, the gap between the sticker and the label can beprovided simply by putting the label on the housing so as to cover theindentation. Therefore, the gap between the sticker and the label can beformed without projecting the contours of the housing.

As the developing cartridge according to a tenth aspect of theinvention, in the ninth aspect of the invention, the communicationpassage is a groove formed on the peripheral surface of the housing. Thegroove is formed so as to extend to a side face of the depression.

According to the invention, the groove is formed on the surface of thehousing for use as the communication passage, so that the communicationpassage can be formed without projecting the contours of the housing.Therefore, the contours of the housing can be shaped almost like thoseof the housing in the related art, and the gap and the communicationpassage can be provided without upsizing the developing cartridge morethan necessary.

As the developing cartridge according to an eleventh aspect of theinvention, in the tenth aspect of the invention, the groove is formed soas to extend to an end face of the housing.

According to the invention, the groove used as the communication passageis formed so as to extend to the end face of the housing from the sideface of the depression, so that the depression and the groove formed onthe peripheral surface of the housing can be covered with the label, andit is made possible to hide the depression and the groove from the labelindication face.

As the developing cartridge according to a twelfth aspect of theinvention, in the ninth aspect of the invention, the communicationpassage is constituted by a cut part formed on the periphery of thelabel and a side face of the depression.

According to the invention, the housing need not be formed in thesurface with any groove, etc., as the communication passage, so that theadhesive surface of the label becomes uniform. That is, an unevenportion of a groove, etc., need not be formed in the margin of thedepression to bond the label and the adhesive surface of the label canbe made uniform without bonding the label to an uneven portion and byextension the label can be prevented from peeling off.

As the developing cartridge according to a thirteenth aspect of theinvention, in the eighth aspect of the invention, the developingcartridge further includes gap securing means which secures the gapbetween the sticker and the label.

According to the invention, the sticker and the label can be preventedfrom coming in intimate contact with each other or bonding together forblocking the communication passage to allow the gap and the atmosphereto communicate with each other.

As the developing cartridge according to a fourteenth aspect of theinvention, in the thirteenth aspect of the invention, the gap securingmeans is so configured that the back of the label opposed to the stickeris not provided with an adhesive.

According to the invention, no adhesive exists on the back of the label,the opposed portion to the sticker, namely, the portion has no adhesiveforce, so that the label can be prevented from bonding to the sticker.

As the developing cartridge according to a fifteenth aspect of theinvention, in the thirteenth aspect of the invention, the back of thelabel is fully provided with an adhesive and the gap securing means isso configured that the back of the label opposed to the sticker isprovided with adhesion prevention means.

According to the invention, the adhesion prevention means having noadhesion, such as paper, a cloth, or a plastic sheet, exists on the backof the label, thereby preventing the label from bonding to the sticker.

As the developing cartridge according to a sixteenth aspect of theinvention, in the fifteenth aspect of the invention, the adhesionprevention means is a release sheet put on the back of the label.

According to the invention, only the position opposed to the sticker, ofthe original release sheet put on the back of the label is left, wherebybonding of the label to the sticker with the adhesive existing on theback of the label can be prevented.

As the developing cartridge according to a seventeenth aspect of theinvention, in the sixteenth aspect of the invention, the release sheetis formed with a drop prevention portion projected from an outerperiphery of the release sheet. The drop prevention portion issandwiched between the label and the surface of the housing.

According to the invention, the adhesive of the label adheres to thesurface of the housing on both sides of the drop prevention portion andthus the drop prevention portion is sandwiched between the label and thesurface of the housing. Accordingly, the release paper can be preventedfrom peeling off and dropping from the back of the label

As the developing cartridge according to an eighteenth aspect of theinvention, in the sixteenth aspect of the invention, the release sheethas one side to which a release agent is applied and an opposite side towhich no release agent is applied, the release paper is peeled off andis turned inside out, and the side of the release paper to which norelease agent is applied is again put on the position where the releasepaper was provided in the beginning, whereby the adhesion preventionmeans can be formed.

According to the invention, the side of the release paper to which norelease agent is applied is put on the adhesive face of the label, sothat the release sheet does not drop from the label and can function asthe adhesion prevention means.

As the air communication unit of the developing cartridge according toan nineteenth aspect of the invention, an air communication unit of adeveloping cartridge used with a rotary developing unit for rotatingaround a rotation shaft with a plurality of developing cartridges placedtherein, thereby bringing the selected developing cartridge adjacent toa photoconductor drum in an image formation apparatus and moving tonerin the developing cartridge to the photoconductor drum, the developingcartridge which includes: a housing, which has a peripheral surface andtwo end faces of both sides of the peripheral surface; and a tonerstorage portion, which is formed in the housing for storing toner. Acommunication hole is formed in the peripheral surface. Thecommunication hole is sealed by a sticker which has minute holes forallowing air to flow and preventing the toner from passing through.

According to the invention, the rotary developing unit rotates, wherebythe toner in the housing drops in a stroke, so that the air below thetoner at the time is pushed out in a stroke through the communicationholes formed in the lower side of the peripheral surface of the housingand on the other hand, the outside air can be forcibly sucked into thespace occupied by the toner through the communication holes formed inthe upper side of the peripheral surface of the housing.

As the air communication unit of the developing cartridge according to atwentieth aspect of the invention, in the nineteenth aspect of theinvention, a label is put on the sticker. The label is formed with anair hole for allowing air to flow.

According to the invention, the presence of the communication hole canbe hidden by the label. On the other hand, the label is formed with theair hole and thus the discharging effect of air and the suction effectof the outside air remain unchanged.

As the air communication unit of the developing cartridge according toclaim 21, a label is put on the housing so as to have a gap between thelabel and the sticker. A communication passage which communicates thegap to an atmosphere is formed.

According to the invention, even if a label not formed with an air holefor allowing air to flow is used, the label does not block the minuteholes of the sticker and the discharging effect of air and the suctioneffect can be provided.

As the air communication unit of the developing cartridge according to atwenty-second aspect of the invention, in the twentieth aspect of theinvention, the air communication unit of the developing cartridge whichfurther includes gap securing means which secures the gap between thesticker and the label.

According to the invention, the sticker and the label can be preventedfrom coming in intimate contact with each other or bonding together forblocking the communication passage to allow the gap and the atmosphereto communicate with each other.

As the toner cartridge according to a twenty-third aspect of theinvention, a toner cartridge which includes a housing, which has aperipheral surface and two end faces formed on both sides of theperipheral surface, a toner containing space surrounded by theperipheral surface and two end faces which contains toner therein, andthe housing having a communication hole which communicates the tonercontaining space with an exterior; and a sticker, which is arranged soas to seal the communication hole. The sticker has minute holes forallowing air to flow and preventing the toner from passing through.

According to the invention, even if the toner cartridge having no membersuch as a developing roller or having the member in separately, theeffect same as the effect described in the first aspect can be obtained.In other words, according to the invention, the rotary developing unitrotates, whereby the toner in the housing drops in a stroke, so that theair below the toner at the time is pushed out in a stroke through thecommunication holes formed in the lower side of the peripheral surfaceof the housing and on the other hand, the outside air can be forciblysucked into the space occupied by the toner through the communicationholes formed in the upper side of the peripheral surface of the housing.

As the toner cartridge according to a twenty-fourth aspect of theinvention, in the twenty-third aspect of the invention, the peripheralsurface of the housing has an upper face and a lower face. Thecommunication hole is formed in either or both of the upper face and thelower face.

According to the invention, even if the toner cartridge having no membersuch as a developing roller or having the member in separately, theeffect same as the effect described in the first aspect can be obtained.In other words, according to the invention, the presence of thecommunication hole can be hidden by the label. On the other hand, thelabel is formed with the air hole and thus the discharging effect of airand the suction effect of the outside air remain unchanged.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a sectional side view to show an image formation apparatusincluding developing cartridges each having an air communication unitaccording to the invention.

FIG. 2 is a perspective view of a rotary developing unit according tothe invention.

FIG. 3 is a perspective view to show the developing cartridge in a statein which an upper housing member and a lower housing member are openedin arrow directions according to the invention.

FIG. 4 is a sectional side view of the developing cartridge according tothe invention.

FIGS. 5(a) to 5(d) are front views to show four embodiments of throughholes formed in the housing.

FIGS. 6(a) and 6(b) are drawings to show motion of toner in each of thedeveloping cartridges 12C and 12K when the rotary developing unitrotates from the state shown in FIG. 6(a) to the state shown in FIG.6(b) with attention focused on the developing cartridges according tothe invention.

FIG. 7 is a side view to show a state in which abutment regulationrollers provided on a developing roller of the developing cartridgecollide with a photoconductor drum according to the invention.

FIG. 8(a) is a front view to show the whole of a roller support frameaccording to the invention; FIG. 8(b) is an enlarged view of the leftportion of the roller support frame; and FIG. 8(c) is a sectional sideview to show the surroundings of a roller end seal member and the rollersupport frame.

FIG. 9(a) is a sectional view to show how a shaft is supported with theleft of the developing roller in FIG. 3 broken away according to theinvention, and FIG. 9(b) is a sectional view to show how the shaft issupported with the right of the developing roller in FIG. 3 broken away.

FIG. 10 is a perspective view to show the roller support frame and asupply roller and the developing roller supported on the roller supportframe according to the invention.

FIG. 11 is a perspective view from a label indication face to show afirst embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label according to the invention.

FIG. 12 is a perspective view to show the surface shape of a housing inFIG. 11.

FIG. 13 is a perspective view to show a state in which a sticker is puton an indentation in FIG. 12.

FIG. 14 is a sectional view taken on line XIIII-XIIII in FIG. 11.

FIG. 15 is a perspective view from the housing end face side to show asecond embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label according to the invention.

FIG. 16 is a perspective view from the label indication face of the aircommunication unit in FIG. 15.

FIG. 17 is a perspective view to show the surface shape of housing inFIG. 16.

FIG. 18 is a perspective view to show a state in which a sticker is puton an indentation in FIG. 17.

FIG. 19 is a perspective view from a label indication face to show athird embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label according to the invention.

FIG. 20 is a sectional view to show an embodiment wherein gap securingmeans is provided for securing a gap between a sticker and a label.

FIG. 21 shows an embodiment wherein release paper is formed with a dropprevention portion.

FIG. 22 shows an embodiment of a label having a portion having noadhesive.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the accompanying drawings, there are shown preferredembodiments of the invention. FIG. 1 is a sectional side view to show animage formation apparatus 1 including developing cartridges each havingan air communication unit according to the invention. In the imageformation apparatus 1, a photoconductor drum 5 is provided in anapparatus main unit 3 for rotation in the direction of an arrow 7 acharger 9 of charging means, a rotary developing unit 11 for holdingdeveloping cartridges of developing means, and a cleaning member 13 areprovided around the photoconductor drum 5 in the rotation direction 7. Acharge bias is applied to the charger 9 from a charge bias circuit (notshown) and the charger 9 can uniformly charge the outer peripheralsurface of the photoconductor drum 5.

A light exposure unit 15 is provided below the rotary developing unit 11and laser light L is applied from the light exposure unit 15 to theouter peripheral surface of the photoconductor drum 5 charged by thecharger 9. The light exposure unit 15 scans laser light L over thephotoconductor drum 5 in response to the image data provided byexpanding an image formation command into an image, thereby forming anelectrostatic latent image corresponding to the image formation commandon the photoconductor drum 5.

The electrostatic latent image thus formed is developed in toner by therotary developing unit 11. That is, the embodiment, the rotarydeveloping unit 11 is provided with a yellow developing cartridge 12Y, acyan developing cartridge 12C, a magenta developing cartridge 12M, and ablack developing cartridge 12K for rotation on a rotation shaft 31 ofthe rotary developing unit 11. As the circumferential positions of thedeveloping cartridges 12Y, 12C, 12M, and 12K are determined, thedeveloping cartridges 12Y, 12C, 12M, and 12K can be selectively broughtadjacent to the photoconductor drum 5 for supplying toner to the surfaceof the photoconductor drum 5. Accordingly, the electrostatic latentimage on the photoconductor drum 5 is rendered visible in the selectedtoner color. FIG. 1 shows the state in which the yellow developingcartridge 12Y supplies toner to the photoconductor drum 5. To describe“top, upper, above, etc.,” or “bottom, lower, below, etc.,” with respectto the developing cartridges, the orientation of the yellow developingcartridge 12Y in FIG. 1 is used as the reference.

A transfer unit 19 is provided above the space from the rotarydeveloping unit 11 to the cleaning member 13. The transfer unit 19includes an intermediate transfer belt 21 placed on a plurality ofrollers and a drive member (not shown) for rotating the intermediatetransfer belt 21. A toner image developed by the rotary developing unit11 is primary-transferred onto the intermediate transfer belt 21 of thetransfer unit 19 in a primary transfer area 17. The toner remaining anddeposited on the outer peripheral surface of the photoconductor drum 5after the primary transfer is scratched by the cleaning member 13 at therotation position in the rotation direction indicated by the arrow 7 inFIG. 1 from the primary transfer area 17.

To transfer a color image to a sheet member S, the color toner imagesformed on the photoconductor drum 5 are superimposed on the intermediatetransfer belt 21 to form a color image and the color image issecondary-transferred onto the sheet member S taken out from a cassette25 in a secondary transfer area 23. The sheet member S with the colorimage thus formed thereon is passed through a fuser unit 27 and istransferred to an ejection tray section 29 provided on the top face ofthe apparatus main unit 3.

Next, the configuration and the operation of the rotary developing unit11 included in the image formation apparatus 1 in FIG. 1 will bediscussed. FIG. 2 is a perspective view of the rotary developing unit11. As shown in FIG. 2, the rotary developing unit 11 has the rotationshaft 31 at the center and a support frame 35, made up of four frameelements 33 which are provided around the rotation shaft 31 and formedat 90-degree intervals, is fixed to the rotation shaft 31. A storagesection 37 is provided between the frame elements 33. The four colordeveloping cartridges 12Y, 12C, 12M, and 12K are stored in the storagesections 37 and are fixed to the support frame 33 by metal fittings (notshown). In FIG. 2, only the developing cartridge 12Y is shown forsimplicity.

A drive member (not shown) is connected to the rotation shaft 31 througha clutch. As the drive member is driven, the support frame 35 can berotated for selectively positioning any one of the four developingcartridges 12Y, 12C, 12M, 12K at the developing position opposed to thephotoconductor drum 5 (in FIG. 1, the position of the developingcartridge 12Y).

The developing cartridges 12Y, 12C, 12M, and 12K held on the supportframe 35 have the same configuration. Therefore, in the description thatfollows, the developing cartridges 12Y, 12C, 12M, and 12K arecollectively called the developing cartridge 12.

The developing cartridge 12 has an upper housing member 41 and a lowerhousing member 42 combined in one piece to form a housing 43 as the mainbody. FIG. 3 shows a state in which the upper housing member 41 and thelower housing member 42 are opened in the arrow directions.

A toner storage portion 45 for storing toner is formed in the housing 43and is formed with a plurality of inclined agitation pieces 51 foragitating toner 47. When the rotary developing unit 11 rotates on therotation shaft 31, the toner 47 drops along the agitation pieces 51 andthus is agitated in the toner storage portion 45.

A supply roller 53 (also called S roller) having a surface formed of aurethane sponge is placed in the toner storage portion 45 for rotation.As shown in FIGS. 3 and 4, a developing roller 55 (also called D roller)is placed on the outside of the supply roller 53 in a state in which thedeveloping roller 55 is in contact with the supply roller 53. When thesupply roller 53 rotates in the arrow direction in a state in which thetoner 47 stored in the housing 43 is supported on the surface of thesupply roller 53, the developing roller 55 rotates in the arrowdirection in FIG. 4 at lower speed than the supply roller 53 whilereceiving the toner 47 on the outer peripheral surface of the developingroller 55 from the supply roller 53. In the example, the supply roller53 rotates at the speed 1.5 times that of the developing roller 55.

The developing roller 55 rotates while coming in contact with thephotoconductor drum 5, and the toner 47 supported on the developingroller 55 is deposited on the surface of the photoconductor drum 5 at adeveloping position 39. Thus, the toner 47 from the supply roller 53 isrubbed against the surface of the developing roller 55 to form a tonerlayer of a predetermined thickness (for example, about 10 μm to 20 μm),and this toner layer is moved to the photoconductor drum 5 in a similarmanner.

As shown in FIG. 2 and FIG. 5(a), the upper housing member 41 forming apart of the housing 43 is formed in a top face 57 with communicationholes 61 to allow air in the toner storage portion 45 to communicatewith the atmospheric pressure. A sticker 63 formed with a large numberof minute holes each of the size to allow air to pass through andprevent toner from passing through is put on each of the communicationholes 61. As the air communication means communicated with the inside ofthe toner storage portion 45 is provided on the top face 57 of the upperhousing member 41, when the rotary developing unit 11 rotates on therotation shaft 31, the toner 47 drops, thereby pushing out the air belowthe toner through the communication holes 61, so that the air in thetoner storage portion 45 can be interchanged.

FIGS. 6(a) and 6(b) are drawings to show motion of the toner 47 in eachof the developing cartridges 12C and 12K when the rotary developing unit11 rotates from the state shown in FIG. 6(a) to the state shown in FIG.6(b) with attention focused on the developing cartridges 12C and 12K.The sticker 63 is not shown in FIGS. 6(a) and 6(b).

In FIG. 6(a), toner 47K in the developing cartridge 12K is positioned inthe lower housing member 42 and then when the rotary developing unit 11rotates to the position shown in FIG. 6(b), the toner 47K in thedeveloping cartridge 12K drops and moves to the upper housing member 41.At this time, air in an area 65 of space in the toner storage portion 45is expelled from the toner storage portion 45 through the communicationholes 61 by the toner 47K dropping so as to cover from the upper side.

The structure of putting the sticker 63 on the communication hole 61 maybe formed on the lower housing member 42. The structure of forming thecommunication holes 61 in the lower housing member 42 is shown in thedeveloping cartridge 12C. The communication holes 61 may be formed inboth the upper housing member 41 and the lower housing member 42 of onedeveloping cartridge 12.

To form the communication holes 61 in the lower housing member 42, whenthe rotary developing unit 11 rotates from the state in which toner 47Cin the developing cartridge 12C is positioned in the upper housingmember 41 as shown in FIG. 6(a) to the position shown in FIG. 6(b), thetoner 47C in the developing cartridge 12C drops and moves to the lowerhousing member 42. At this time, air in an area 66 of space in the tonerstorage portion 45 is expelled through the communication holes 61 formedin the lower housing member 42 by the toner 47C dropping so as to coverfrom the upper side.

As the air in the toner storage portion 45 is thus allowed to circulatefreely through the communication holes 61, a negative pressure is notdeveloped in the toner storage portion 45 in the process in which thetoner 47 in the toner storage portion 45 is consumed, making it possibleto maintain the pressure in the toner storage portion 45 always equal tothe atmospheric pressure. If a heat generation source exists in theproximity of the toner storage portion 45, the air in the toner storageportion 45 can be prevented from being expanded and becoming apressurization state by heat from the heat generation source. Therefore,the effect of the pressure in the toner storage portion 45 can beexcluded and the toner supply state from the toner storage portion 45can be always kept constant.

The communication hole 61 with the sticker 63 put thereon as describedabove needs to be formed at such a position to be able to push out or incontrast absorb the air in the housing 43, namely, “breathe” with motionof the toner 47 as the rotary developing unit 11 rotates. The aircommunication unit of the invention is effective particularly for adeveloping cartridge having no agitator. In the developing cartridgeincluding the air communication unit of the invention, the toner 47 isagitated by rotation of the rotary developing unit 11 for properly usingthe four color toners, by rotation of the rotary developing unit 11intended only for agitating the toner after the termination of print,and by rotation of the rotary developing unit 11 intended only foragitating the toner when the image formation apparatus has stopped for along time. At the time, as air circulates through the communicationholes 61, motion of the toner in the housing is promoted and theagitation efficiency can be enhanced accordingly.

The communication hole 61 may be formed at any position in the upperhousing member 41 or the lower housing member 42 if it is a portionhaving a breath function as mentioned above; preferably thecommunication holes 61 are formed in the vicinity of both ends of theupper housing member 41 or the lower housing member 42. The reason willbe discussed with reference to FIG. 7.

As shown in FIG. 7, the developing roller 55 is attached to a rotationshaft 67 and an abutment regulation roller 69 having a diameter a littlelarger than that of the developing roller 55 is provided at both ends ofthe rotation shaft 67 for rotation. In FIG. 1, when the rotarydeveloping unit 11 rotates and the yellow developing cartridge 12Y, forexample, approaches the photoconductor drum 5, the peripheral surfacesof the two abutment regulation rollers 69 of the developing cartridge12Y collide lightly with the photoconductor drum 5, defining thedistance between the peripheral surface of the developing roller 55 andthat of the photoconductor drum 5 as a predetermined distance. Thepredetermined distance is drawn comparatively large in FIG. 7, butactually is an extremely small distance of 1 mm or less.

The vibration produced when the peripheral surfaces of the abutmentregulation rollers 69 collide with the photoconductor drum 5 easilypropagates particularly to the vicinity of both ends of the housing 43in the proximity of the abutment regulation rollers and thus the toner47 in the vicinity of both ends of the housing 43 easily drops in astroke due to the vibration. Thus, preferably the communication holes 61are formed in the vicinity of both ends of the upper housing member 41or the lower housing member 42, particularly at the positionscorresponding to the positions of the two abutment regulation rollers69.

As the communication holes 61, a comparatively large hole may be formedin each of both ends of the housing 43 as shown in FIG. 5(a); a group offour (or any number of) small holes in place of a large hole may beformed in each of both ends of the housing 43 as shown in FIG. 5(b); ora plurality of small holes may be formed not only in both ends of thehousing 43, but also in the center of the housing 43 as shown in FIG.5(c). The sticker 63 having minute holes is put on every small hole, asdescribed above.

A label 71 describing caution on handling, etc., for example, may be puton the sticker 63 having minute holes put on the communication hole 61,as shown in FIG. 5(d). As shown in a sectional view on an enlarged scalein FIG. 5(d), the label 71 is formed with air holes 73 for allowing airto circulate, thereby ensuring the air communication function throughthe communication hole 61.

To use a label 71 not formed with air holes 73 for allowing air tocirculate, the label 71 is put on the housing 43 so as to have a gap 201between the label 71 and the sticker 63 and a communication passage 202for allowing the gap 201 and an atmosphere 200 to communicate with eachother, whereby the presence of the communication hole 61 can be hiddenwithout blocking the minute holes of the sticker 63, as in embodimentsshown in FIGS. 11 to 20. The embodiments will be discussed below:

FIG. 11 is a perspective view from the label indication face to show afirst embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label. FIG. 12 is a perspectiveview to show the surface shape of a housing in FIG. 11. FIG. 13 is aperspective view to show a state in which a sticker is put on anindentation in FIG. 12. FIG. 14 is a sectional view taken on lineXIIII-XIIII in FIG. 11.

The air communication unit of the developing cartridge 12 shown in FIG.11 includes communication passages 202 on the peripheral surface ofhousing 43 for enabling the air in the toner storage portion 45 to bemade fresh. To begin with, the configuration of the air communicationunit of the developing cartridge 12 in the embodiment will be discussedwith reference to FIGS. 12 and 13, followed by description about acommunication path from the toner storage portion 45 to the atmosphere200 with reference to FIG. 14.

FIG. 12 shows the shape of the housing 43 in the surroundings of the aircommunication unit of the developing cartridge 12 in the embodiment. Thehousing 43 is formed on a surface with a roughly rectangular depression203 long in the axial direction of the developing roller 55. A pluralityof communication holes 61 are made in a bottom 203B of the depression203. Further, a plurality of grooves 204 are formed so as to extend inthe axial direction of the developing roller 55, and reach a side 203Aof the depression 203.

A sticker 63 is formed roughly like the same shape as the depression 203as shown in FIG. 13 and is put on the bottom 203B so as to block thecommunication holes 61.

As shown in FIG. 14, a label 71 is put on the housing 43 so as to have agap 201 between the label 71 and the sticker 63. At this time, thegroove 204 formed on the surface of the housing 43 forms thecommunication passage 202 from the portion of the surface of the housing43 where the label 71 is not put to the side 203A of the depression 203.This means that the groove 204 forms the communication passage 202 toallow the gap 201 and the atmosphere 200 to communicate with each other.

Further, the sticker 63 put on the bottom 203B is similar to the stickerin FIGS. 2 and FIG. 5, etc., and is formed with a large number of minuteholes each of the size to allow air to pass through and prevent tonerfrom passing through, and the gap 201 and the toner storage portion 45communicate with each other.

Therefore, in the developing cartridge 12 shown in FIGS. 11 to 14, thetoner storage portion 45 and the gap 201 communicate with each other andthe gap 201 and the atmosphere 200 communicate with each other, so thatthe toner storage portion 45 and the atmosphere 200 communicate witheach other with the gap 201 between as indicated by arrows 206, makingit possible to make fresh the air in the toner storage portion 45.

Also in the embodiment, the communication holes 61 in the developingcartridge 12 may be formed in either the upper housing member 41 or thelower housing member 42 or may be formed in both the upper housingmember 41 and the lower housing member 42. Preferably, the communicationholes 61 are formed in the surroundings of the abutment regulationroller 69 as shown in FIGS. 11 to 13. For simplicity, the abutmentregulation roller 69 is not shown in FIGS. 2, 3, 9, and 10.

The gap 201 is not limited to the form shown in the embodiment and canalso be formed by heaping up the surroundings of the communication hole61 of the housing 43 in the related art to provide a bank-like enclosureand putting the label 71 on the enclosure. At this time, it is alsopossible to provide the communication passage 202 by making a hole inthe enclosure.

However, as shown in the embodiment, the gap 201 and the communicationpassage 202 are provided by forming the depression 203 and the groove204 in the surface of the housing 43, whereby the contours of thehousing 43 can be shaped almost like those of the housing in the relatedart, and the gap 201 and the communication passage 202 can be providedwithout upsizing the developing cartridge 12 more than necessary.

FIG. 15 is a perspective view from the housing end face side to show asecond embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label. FIG. 16 is a perspectiveview from the label indication face of the air communication unit inFIG. 15. FIG. 17 is a perspective view to show the surface shape ofhousing in FIG. 16. FIG. 18 is a perspective view to show a state inwhich a sticker is put on an indentation in FIG. 17.

In the air communication unit of the developing cartridge 12 shown inFIG. 15, communication passages 202 formed in housing 43 are formed soas to reach an end face 43A of the housing 43. When the aircommunication unit of the developing cartridge 12 is viewed from theindication face side of a label 71, the label 71 is only put and thepresence of the air communication unit is hidden, as shown in FIG. 16.The configuration of the air communication unit of the developingcartridge 12 in the embodiment will be discussed with reference to FIGS.17 and 18.

FIG. 17 shows the shape of the housing 43 in the surroundings of the aircommunication unit of the developing cartridge 12 in the embodiment. Thehousing 43 is formed on a surface with a roughly rectangular depression203 long in the axial direction of the developing roller 55. A pluralityof communication holes 61 are formed on a bottom 203B of the depression203. Further, a plurality of grooves 204 are formed so as to extend inthe axial direction of the developing roller 55, and reach the end face43A of the housing 43 from a side 203A of the depression 203.

A sticker 63 is put on the bottom 203B of the depression 203 so as toblock the communication holes 61 as shown in FIG. 18 and further thelabel 71 is put on the housing 43 so as to cover the depression 203 andthe grooves 204 as shown in FIG. 16.

Also in the embodiment, as in the first embodiment of the aircommunication unit of the developing cartridge 12 having the gap 201formed between the sticker 63 and the label 71, the toner storageportion 45 and a gap 201 communicate with each other and the gap 201 andan atmosphere 200 communicate with each other, so that the toner storageportion 45 and the atmosphere 200 communicate with each other with thegap 201 between, making it possible to interchange the air in the tonerstorage portion 45.

According to the embodiment, as already described, the communicationpassages 202 are formed in the end face 43A of the housing and are hardto be conspicuous and cannot be recognized from the indication face sideof the label 71. Thus, the user can be prevented from carelessly cuttingthe label 71 from the communication passage 202 and peeling off thesticker 63 so that toner 47 is released.

The contours of the housing 43 can be shaped almost like those of thehousing in the related art, and the gap 201 and the communicationpassage 202 can be provided without upsizing the developing cartridge 12more than necessary.

Also in the embodiment, the communication holes 61 in the developingcartridge 12 may be formed in either the upper housing member 41 or thelower housing member 42 or may be formed in both the upper housingmember 41 and the lower housing member 42. Preferably, the communicationholes 61 are formed in the surroundings of the abutment regulationroller 69 as shown in FIGS. 15 to 17.

FIG. 19 is a perspective view from the label indication face to show athird embodiment of air communication unit of developing cartridge witha gap provided between a sticker and a label. In FIG. 19, a label 71 isdrawn where the end face 43A side of a housing 43 is not shown so thatthe shape of an depression 203 can be checked.

The housing 43 is formed on a surface with the roughly rectangulardepression 203 long in the axial direction of the developing roller 55,and a plurality of communication holes 61 are formed on a bottom 203B ofthe depression 203.

A sticker 63 is put on the bottom 203B of the depression 203 so as toblock the communication holes 61, and the label 71 is put on the housing43 so as to almost cover the depression 203.

The embodiment differs in the first or second embodiment of the aircommunication unit of the developing cartridge 12 having the gap 201formed between the sticker 63 and the label 71 in that the housing 43 isnot formed with any groove 204 for forming a communication passage 202.A part of the periphery of the label 71 is cut to form a cut part 71Afor allowing the toner storage portion 45 and atmosphere 200 tocommunicate with each other.

That is, a communication passage 202 is constituted by the cut part 71Aformed on the periphery of the label 71 and a side 203A of thedepression 203.

Also in the embodiment, as in the first and second embodiments of theair communication unit of the developing cartridge 12 having the gap 201formed between the sticker 63 and the label 71, the toner storageportion 45 and a gap 201 communicate with each other and the gap 201 andan atmosphere 200 communicate with each other, so that the toner storageportion 45 and the atmosphere 200 communicate with each other with thegap 201 between, making it possible to interchange the air in the tonerstorage portion 45.

According to the embodiment, the housing 43 need not be formed in thesurface with any groove 204, etc., as the communication passage 202, anddesign change made to the housing 43 in the related art can beminimized.

According to the invention, the housing 43 need not be formed in thesurface with any groove 204, etc., as the communication passage 202, sothat the adhesive surface of the label 71 becomes uniform. That is, anuneven portion of a groove 202, etc., need not be formed in the marginof the depression 203 to bond the label 71 and the adhesive surface ofthe label 71 can be made uniform without bonding the label 71 to anuneven portion and by extension the label 71 can be prevented frompeeling off.

The contours of the housing 43 can be shaped almost like those of thehousing in the related art, and the gap 201 and the communicationpassage 202 can be provided without upsizing the developing cartridge 12more than necessary.

Also in the embodiment, the communication holes 61 in the developingcartridge 12 may be formed in either the upper housing member 41 or thelower housing member 42 or may be formed in both the upper housingmember 41 and the lower housing member 42. Preferably, the communicationholes 61 are formed in the surroundings of the abutment regulationroller 69 as shown in FIG. 19.

The embodiments wherein the label 71 does not require any air hole 73for allowing air to flow have been described. The three embodimentspreviously described with reference to FIGS. 11 to 19 are embodimentswherein the label 71 does not require any air hole 73 for allowing airto flow; the label 71 may be formed with an air hole 73 for allowing airto flow. To use the label 71 formed with the air hole 73, thedischarging effect of the air in the housing 43 and the suction effectof the outside air into the housing 43 are sill more enhanced.

Next, another embodiment of the invention will be discussed. Forexample, in the embodiment previously described with reference to FIG.19, to put the label 71 on the surface of the upper housing member 41,release paper put on the back of the label 71 is stripped and the falseface with an adhesive is put toward the sticker 63. However, in theportion where the false face of the label 71 is opposed to the sticker63, a human being presses the label 71 from above by mistake or thelabel 71 warps downward, whereby it is feared that the false face may bebonded to the label 71 and consequently it may be made impossible tosecure the communication passage from the surface of the sticker 63 tothe atmosphere.

Then, in the embodiment, gap securing means is provided for securing agap between a sticker 63 and a label 71. FIG. 20 specifically shows gapsecuring means. The embodiment differs from the embodiment previouslydescribed with reference to FIG. 14 in that release paper 131 ofadhesion prevention means is placed at a position opposed to the sticker63, on the lower fade of the label 71. Members or parts identical withthose previously described with reference to FIG. 14 are denoted by thesame reference numerals in FIG. 20.

FIG. 21 is a drawing to show the position at which the release paper 131is placed on the back of the label 71 and the shape of the label. Asseen in the figure, the release paper is not provided and an adhesive133 is exposed in the surrounding portion for putting the label 71 onthe upper housing member 41, and the release paper 131 is not strippedand remains in other portions, namely, an inner area of the label 71 notput on the upper housing member 41. Since an adhesive is applied fullyto the back of the label 71 for the reason of cost reduction, therelease paper is provided on the full back of the label 71 in thebeginning. As shown in FIG. 21, the boundary between the portion inwhich the release paper is left intact and the portion in which therelease paper is stripped and the adhesive is exposed is notched, andthe release paper only in the surrounding portion of the back isstripped at the use time, whereby the label 71 becomes as shown in FIG.21.

In FIG. 21, a portion denoted by reference numeral 135 is a dropprevention portion projected from the outer periphery of the remainingrelease paper 131. The drop prevention portion 135 is formed so as toproject to only a part of the adhesive 133 on the periphery of the backof the label 71. In FIG. 21, the drop prevention portion 135 is formedonly at two places at the centers of the long sides of the label 71; inaddition, the drop prevention portion 135 may be provided in thevicinity of the center of the short side of the label 71 and in a cornerof the label 71.

As the drop prevention portion 135 is provided, the adhesive of thelabel 71 adheres to the surface of the upper housing member 41 on bothsides of the drop prevention portion 135 and thus the drop preventionportion 135 is sandwiched between the label 71 and the surface of thehousing. Accordingly, the release paper 131 can be prevented frompeeling off and dropping from the back of the label 71. As theconfiguration of securing a gap between the label 71 and the sticker 63using the release paper 131 as in the embodiment is adopted, the releasepaper 131 can be easily stripped and other portions can be easilyrecycled at the recycling time of the developing cartridge.

In the embodiment, the release paper 131 is named as the adhesionprevention means, but paper, a cloth, a plastic sheet, or the likehaving no adhesion rather than the release paper 131 can also be put onthe position opposed to the sticker 63 to cover the adhesive face of thelabel 71 for inhibiting adhesion of the sticker 63 and the label 71.When paper, a cloth, a plastic sheet, or the like having no adhesion isput on the label 71, if there is no risk of dropping, the dropprevention portion 135 need not be formed.

Using the fact that release paper usually has one side to which arelease agent is applied and the other side to which no release agent isapplied, the release paper 131 may be once peeled off, for example, fromthe state in which the release paper 131 is provided as shown in FIG.21, and may be turned inside out and again put on the same position ofthe label 71. In doing so, the side with no release agent appliedthereto is put on the label 71 and thus the possibility that the releasepaper 131 will drop from the label 71 is extremely small. Therefore, toadopt such a method, the drop prevention portion 135 need not be formed.

As another example of the gap securing means, a configuration in which aportion 137 not provided with an adhesive on the back of the label 71 isformed in the portion of the label 71 opposed to the sticker 63 as shownin FIG. 22, a configuration in which a plurality of thin projectionsextending from the sticker 63 are formed in the portion of the label 71opposed to the sticker 63 to secure the distance between the sticker 63and the label 71 for maintaining communication of air although notshown, or the like can be named.

Next, the structure of the surroundings of the developing roller 55 inthe developing cartridge 12 will be discussed. A roller support frame 75is fixed to the housing 43 of the developing cartridge 12. The rollersupport frame 75 is formed all of metal and is made up of a lower framepart 77, side frame parts 79 a and 79 b bent at 90 degrees from bothends of the lower frame part 77, and an upper frame part 83 connected tothe upper ends of the side frame parts 79 a and 79 b by screws 81. Thedeveloping roller 55 can be placed in the area surrounded by the lowerframe part 77, the upper frame part 83, and the two side frame parts 79a and 79 b.

A blade fixing frame 85 is attached to the lower frame part 77 by aplurality of fixing screws 87, and a blade support frame 89 made ofphosphor bronze is provided between the blade fixing frame 85 and thelower frame part 77, as shown in FIG. 4. A regulation blade 91 made ofrubber, a resin material, etc., is put on the top of the tip of theblade support frame 89, and is pressed at a constant pressure againstthe peripheral surface of the developing roller 55 over the lengthdirection thereof by the spring return action of the blade support frame89 itself and the elastic return action of a backup sponge 93 (see FIG.4) provided on the lower side of the tip of the blade support frame 89.

The regulation blade 91 has a function of charging the toner 47 to thesame polarity, as the toner 47 rubs with the regulation blade 91. Thetoner thus charged to a predetermined polarity is supplied to thedeveloping roller 55, and the electrostatic latent image on thephotoconductor drum 5 can be developed by the toner 47 on the developingroller 55.

The regulation blade 91 also has a function of uniformly leveling thetoner 47 deposited on the peripheral surface of the developing roller 55so that the thickness of the toner layer finally becomes about 20 μm,for example. Therefore, to even the thickness of the toner 47 in thelength direction of the developing roller 55, it is important for thedeveloping cartridge 12 that the regulation blade 91 is pressed at aconstant pressure against the peripheral surface of the developingroller 55 over the length direction thereof.

To ensure averaging the press pressure of the regulation blade 91against the developing roller 55, the upper frame part 83 is added asthe component of the roller support frame 75 as described above so thatthe roller support frame 75 becomes a closed loop structure.

That is, such a closed loop structure is adopted and the developingroller 55 and the regulation blade 91 are put into a unit, whereby theshape retention of the roller support frame 75 is enhanced. Thus, whenthe developing cartridge 12 is placed in the storage section 37 of therotary developing unit 11 or is detached therefrom, if a considerableforce is applied to the roller support frame 75, the positionalrelationship between the peripheral surface of the developing roller 55and the regulation blade 91 becomes hard to change over the lengthdirection. Accordingly, the regulation blade 91 always continues topress the peripheral surface of the developing roller 55 by a constantforce over the length direction, so that the distribution of the toner47 on the peripheral surface of the developing roller 55 can beprevented from being unbalanced in the length direction of thedeveloping roller 55 and a print failure of inconsistencies in colordensity or the like can be prevented.

Next, the structure of attaching the roller support frame 75 to thelower housing member 42 will be discussed with reference to FIGS. 9(a)and 9(b). FIG. 9(a) shows how a shaft 103 is supported with the left ofthe developing roller 55 in FIG. 3 broken away, and FIG. 9(b) shows howthe shaft is supported with the right of the developing roller 55 inFIG. 3 broken away.

As shown in FIGS. 9(a) and 9(b), a supply roller through hole (notshown) and a developing roller through hole 99 are formed in end faces95 a and 95 b of the lower housing member 42, and shaft retentionmembers 101 a and 101 b are provided outside the end faces 95 a and 95b. Although not shown, both end parts of the shaft of the supply roller53 are supported on a shaft retention section (not shown) extending intothe supply roller through hole from the shaft retention members 101 aand 101 b for rotation.

Both end parts of the shaft 103 of the developing roller 55 aresupported on a shaft retention section 105 extending into the developingroller through hole 99 from the shaft retention members 101 a and 101 bfor rotation. As shown in FIG. 9(a), two holes 106 each a little smallerthan the thread of a screw 107 are formed in the left end face 95 a ofthe lower housing member 42 and the screws 107 are forcibly screwed intothe holes via washers 108, whereby the left shaft retention member 101 aand the left end face 95 a of the lower housing member 42 are fixed. Theleft side frame part 79 a of the roller support frame 75 is also formedwith two holes for screws 107 at the positions matching the holes 106 inthe left end face 95 a of the lower housing member 42. The holes areunloaded holes 109 larger than the threads of the screws 107 and thescrews 107 are inserted into the unloaded holes 109.

On the other hand, as shown in FIG. 9(b), two unloaded holes 113 eachlarger than the thread of a screw 111 are formed in the right end face95 b of the lower housing member 42 and the right side frame part 79 bof the roller support frame 75 is formed with two screw holes 115 eachformed with a female screw for the screw 111 at the match positions. Thescrews 111 are screwed into the unloaded holes 113 and the screw holes115 from holes made in the right shaft retention member 101 b, wherebythe right shaft retention member 101 b, the right end face 95 b of thelower housing member 42, and the right side frame part 79 b are fixed inone piece.

As the result of adopting the configuration, the housing 43 and theroller support frame 75 are fixed to each other on the right side sothat a move in the length direction of the housing is regulated; theside frame part 79 a of the roller support frame 75 is not fixed to theend face 95 a of the lower housing member 42 on the left side. Thus, itis made possible for the housing 43 and the roller support frame 75 tomove freely in the length direction of the housing without receiving themutual effect.

The reason why the configuration is adopted is that the resin of whichthe housing 43 is made has a larger thermal expansion coefficient thanthe metal of which the roller support frame 75 is made and thus thermalchange causes the housing 43 and the roller support frame 75 to differin difference between expansion and contraction (the housing 43 has alarger difference between expansion and contraction than the rollersupport frame 75) and the effect of the difference between expansion andcontraction needs to be eliminated. That is, as the above-describedconfiguration is adopted, distortion of the roller support frame 75caused because they differ in difference between expansion andcontraction can be prevented, so that the abutment pressure of theregulation blade 91 against the outer peripheral surface of thedeveloping roller 55 provided on the roller support frame 75 can becontinuously maintained constant over the length direction, making itpossible to supply toner uniformly over the length direction.

Although not clearly shown in FIG. 9(a) and 9(b), a slight gap is formedbetween the end face 95 a of the lower housing member 42 and the sideframe part 79 a of the roller support frame 75 even in the state inwhich the lower housing member 42 is most contracted.

Next, the structure for preventing the toner 47 from scattering from thetoner storage portion 45 in the housing 43 to the outside will bediscussed. As shown in FIG. 4, a scattering prevention seal member 117is fixed at one end to the upper frame part 83 of the roller supportframe 75 above the developing roller 55, and is pressed at an oppositeend against the developing roller 55 by a backup sponge 119 fixed to thelower housing member 42. Accordingly, scattering of the toner 47 to theoutside from the nip between the developing roller 55 and the upperframe part 83 is prevented.

A seal member 121 is put on the inside of the upper frame part 83 of theroller support frame 75 for blocking the gap between the lower housingmember 42 and the upper frame part 83, thereby preventing the toner 47passing through the backup sponge 119 from scattering to the outside.

Further, as shown in FIGS. 8(c) and 10, a roller end seal member 123abuts both end parts of the peripheral surface of the developing roller55 for preventing the toner 47 from scattering from the end part of thedeveloping roller 55 to the outside. As shown in a partially enlargedview in FIG. 10, the roller end seal member 123 is of a double structurewherein an upper low-friction function member 125 and a lower powderseal function member 127 are stuck together. The upper low-frictionfunction member 125 is formed of a material excellent in durabilityagainst rotation wear to lessen the rotation frictional resistance onthe contact face with the developing roller 55 as much as possible, suchas Fujiron 7000 (registered trademark) (manufactured by Fujiko kabushikikaisha). The lower powder seal function member 127 is formed of amaterial excellent in seal function property of powder of toner, etc.,such as wool felt.

The roller end seal member 123 is fixed on the base end side to theblade support frame 89 or the lower frame part 77 and is supported onthe tip side by the lower housing member 42 from the lower side, but notfixed to the lower housing member 42 and is a free end.

As the tip side of the roller end seal member 123 is made a free end,the following can be circumvented: Since the contact state between theperipheral surface of both ends of the developing roller 55 and theroller end seal member 123 changes delicately over time, only the samepart of the roller end seal member 123 wears out like a groove and thesticker performance is degraded.

According to the invention, the rotary developing unit rotates aroundthe rotation shaft, whereby the toner in the housing drops in a stroke,so that the air below the toner at the time is pushed out in a strokethrough the communication holes formed in the lower side of theperipheral surface of the housing and on the other hand, the outside aircan be forcibly pulled into the space occupied by the toner through thecommunication holes formed in the upper side of the peripheral surfaceof the housing.

If the communication hole is formed in either or both of the upper faceand the lower face of the housing, air is pulled in through thecommunication hole formed in the upper face of the peripheral surface ofthe housing in the beginning and air is pushed out through thecommunication hole formed in the lower face. Then, when the rotarydeveloping unit rotates 180 degrees, the communication holes formed inthe upper and lower faces function in opposite manner. Thus, wheneverthe rotary developing unit rotates, air is discharged and suckedalternately through the same communication hole with a move of toner, sothat rapid pressure adjustment in the housing is made.

In the developing cartridge of the present invention, it is explainedthat a toner cartridge portion for containing the toner and thedeveloping roller portion for moving the toner of the toner cartridgeportion to the photoconductor drum are integrally formed. However, thedeveloping cartridge is not limited to the above configuration. Thetoner cartridge portion and the developing portion may be configured soas to separate each other and the toner cartridge portion, and thedeveloping portion may be integrally attached when they are attached tothe totally developing unit. In other words, the respectivecharacterized configuration of the developing cartridge of the presentembodiment may be preferably used in a case that the respectivecharacterized configurations are applied to a toner cartridge which hasno developing roller.

Although the present invention has been shown and described withreference to specific preferred embodiments, various changes andmodifications will be apparent to those skilled in the art from theteachings herein without deviating from the spirit and scope of thepresent invention.

This patent application is based on Japanese patent application(JP-2002-074011) filed on Mar. 18, 2002, Japanese patent application(JP-2002-250098) filed on Aug. 29, 2002 and Japanese patent application(JP-2003-057192) filed on Mar. 4, 2003, and the contents of the Japanesepatent applications are contained in this patent application forreference.

Industrial Applicability

The rotary developing unit rotates around the rotation shaft, wherebythe toner in the housing drops in a stroke, so that the air below thetoner at the time is pushed out in a stroke through the communicationholes formed in the lower side of the peripheral surface of the housingand on the other hand, the outside air can be forcibly sucked into thespace occupied by the toner through the communication holes formed inthe upper side of the peripheral surface of the housing. Therefore,according to the developing cartridge, the air communication unit of thedeveloping cartridge, and the toner cartridge of the present invention,by using the fact that a rotary developing unit rotates on a rotationshaft to make it possible to forcibly discharge air in a developingcartridge or forcibly suck the outside air for promptly adjusting thepressure in the developing cartridge.

1. A developing cartridge, comprising: a housing, which has a peripheralsurface and two end faces formed on both sides of the peripheralsurface, a toner containing space surrounded by the peripheral surfaceand two end faces which contains toner therein, and the housing having acommunication hole which communicates the toner containing space with anexterior; and a sticker, which is arranged so as to seal thecommunication hole, wherein the sticker has minute holes for allowingair to flow and preventing the toner from passing through.
 2. Thedeveloping cartridge as set forth in claim 1, wherein the peripheralsurface of the housing has an upper face and a lower face; and whereinthe communication hole is formed in either or both of the upper face andthe lower face.
 3. The developing cartridge as set forth in claim 1 or 2further comprising, a developing roller which provides the toner in thetoner containing space to the conductor drum, the developing rollerhaving a rotation shaft to be rotatably attached to the housing; and anabutment regulation roller, which regulates a distance between thedeveloping roller and the conductor drum, and the abutment regulationroller attached to both ends of the rotation shaft of the developingroller, wherein the communication hole is formed in the vicinity of theabutment regulation roller.
 4. The developing cartridge as set forth inclaim 3, wherein the communication hole is formed so as to correspond aposition of the abutment regulation roller.
 5. The developing cartridgeas set forth in claim 3 or 4, wherein the communication hole isconstituted by a plurality of communication holes; and wherein one ofthe communication holes is formed at a center portion of the housing. 6.The developing cartridge as set forth in claim 1, wherein thecommunication hole is constituted by a plurality of small holes.
 7. Thedeveloping cartridge as set forth in claim 1, further comprising alabel, which is put on the sticker, wherein the label is formed with anair hole for allowing air to flow.
 8. The developing cartridge as setforth in claim 1, further comprising a label which is put on the housingso as to have a gap between the label and the sticker, wherein acommunication passage which communicates the gap to an atmosphere isformed.
 9. The developing cartridge as set forth in claim 1, wherein thecommunication hole is provided on a bottom of a depression formed on theperipheral surface of the housing.
 10. The developing cartridge as setforth in claim 9, wherein the communication passage is a groove formedon the peripheral surface of the housing; and wherein the groove isformed so as to extend to a side face of the depression.
 11. Thedeveloping cartridge as set forth in claim 10, wherein the groove isformed so as to extend to an end face of the housing.
 12. The developingcartridge as set forth in claim 9, wherein the communication passage isconstituted by a cut part formed on a periphery of the label and a sideface of the depression.
 13. The developing cartridge as set forth inclaim 8, further comprising gap securing means which secures the gapbetween the sticker and the label.
 14. The developing cartridge as setforth in claim 13, wherein the gap securing means is so configured thata back of the label opposed to the sticker is not provided with anadhesive.
 15. The developing cartridge as set forth in claim 13, whereinthe back of the label is fully provided with an adhesive; and whereinthe gap securing means is so configured that the back of the labelopposed to the sticker is provided with adhesion prevention means. 16.The developing cartridge as set forth in claim 15, wherein the adhesionprevention means is a release sheet which is put on the back of thelabel.
 17. The developing cartridge as set forth in claim 16, whereinthe release sheet is formed with a drop prevention portion projectedfrom an outer periphery of the release sheet; wherein the dropprevention portion is sandwiched between the label and the surface ofthe housing.
 18. The developing cartridge as set forth in claim 16,wherein the release sheet has one side to which a release agent isapplied and an opposite side to which no release agent is applied; andwherein the release sheet is peeled off and is turned inside out, andthe side of the release sheet to which no release agent is applied isagain put on the position where the release sheet is provided in thebeginning so that the adhesion prevention means is formed.
 19. An aircommunication unit of a developing cartridge used with a rotarydeveloping unit for rotating around a rotation shaft with a plurality ofdeveloping cartridges placed therein, thereby bringing the selecteddeveloping cartridge adjacent to a photoconductor drum in an imageformation apparatus and moving toner in the developing cartridge to thephotoconductor drum, the developing cartridge comprising: a housing,which has a peripheral surface and two end faces of both sides of theperipheral surface; and a toner storage portion, which is formed in thehousing for storing toner, wherein a communication hole is formed in theperipheral surface; and wherein the communication hole is sealed by asticker which has minute holes for allowing air to flow and preventingthe toner from passing through.
 20. The air communication unit of thedeveloping cartridge as set forth in claim 19, wherein a label is put onthe sticker; and wherein the label is formed with an air hole forallowing air to flow.
 21. The air communication unit of the developingcartridge as set forth in claim 19, wherein a label is put on thehousing so as to have a gap between the label and the sticker; andwherein a communication passage which communicates the gap to anatmosphere is formed.
 22. The air communication unit of the developingcartridge as set forth in claim 21, further comprising gap securingmeans which secures the gap between the sticker and the label.
 23. Atoner cartridge, comprising: a housing, which has a peripheral surfaceand two end faces formed on both sides of the peripheral surface, atoner containing space surrounded by the peripheral surface and two endfaces which contains toner therein, and the housing having acommunication hole which communicates the toner containing space with anexterior; and a sticker, which is arranged so as to seal thecommunication hole, wherein the sticker has minute holes for allowingair to flow and preventing the toner from passing through.
 24. The tonercartridge as set forth in claim 23, wherein the peripheral surface ofthe housing has an upper face and a lower face; and wherein thecommunication hole is formed in either or both of the upper face and thelower face.